Extracting subterranean hydrocarbons sources may require drilling a hole from the surface to the subterranean geological formation housing the hydrocarbons. Specialized drilling techniques and materials are utilized to form the bore hole and extract the hydrocarbons. Specialized materials utilized in drilling operations include materials for sealing the casing-casing annulus of the wellbore, which may be formulated for specific downhole conditions.
A wellbore is a hole that extends from the surface to a location below the surface to permit access to hydrocarbon-bearing subterranean formations. The wellbore contains at least a portion of a fluid conduit that links the interior of the wellbore to the surface. The fluid conduit connecting the interior of the wellbore to the surface may be capable of permitting regulated fluid flow from the interior of the wellbore to the surface and may permit access between equipment on the surface and the interior of the wellbore. The fluid conduit may be defined by one or more tubular strings, such as casings for example, inserted into the wellbore and secured in the wellbore.
During drilling of a wellbore, cementing the wellbore, or both, lost circulation zones may be encountered and may result in loss of drilling fluid or cementing compositions. In a lost circulation zone, the drilling fluid or cement composition flows out of the wellbore and into the surrounding formation. Lost circulation zones may result in increased cost of the well through increased material costs to replace lost fluids and downtime to remediate the lost circulation zone. Lost circulation zones may be remediated by introducing a lost circulation material into the lost circulation zone to seal off the lost circulation zone to prevent further fluid loss. Conventional lost circulation materials (LCM) can include bridging material, fibrous material, flaky material, cement such as reduced-cure-time cement, and other materials having different particle sizes. While these materials may be effective at mediating many lost circulation zones, these conventional materials are not effective for use as LCM in low-injectivity zones due to the solids content of these materials, which makes injection of these materials into the formation difficult. For example, cement compositions are not generally injectable into low-injectivity zones.
Additionally, during subsequent drilling of the wellbore and production using the well, conventional cement compositions used to isolate lost circulation zones are subjected to temperature and pressure cycling. This temperature and pressure cycling may cause micro-cracks to form in the cement sheath isolating the lost circulation zone from the rest of the wellbore. Fluids, such as gas or liquids, may migrate through these micro-cracks, which may eventually result in additional loss of fluids to the lost circulation zone.